BRACHIOPODA. 
119 
At present we can safely refer to Eumetria only the American forms, E. vera 
and var. costata, Hall, and E. Verneuiliana, Hall, from the Kaskaskia and Warsaw 
limestones of the lower Carboniferous series, which are, perhap'S, all repre¬ 
sentatives of the same species. Of other finely striated species which may 
prove congeneric, is the Retzia serpentina, de Koninck,* but all the Carboniferous 
species with RETziA-like exterior will need most careful scrutiny before their 
generic values can be determined. 
Genus ACAMBONA, White. 1862. 
PLATE LI. 
I860. Retzia, Swallow. Trans. St. Louis Acad. Sci., vol. i, p. 653. 
1862. Acamhona, White. Proc. Boston Society Nat. Hist., vol. ix, p. 27, figs. 1, 2. 
This name was proposed for a large species described as Acamhona prima, and 
its generic characters were given in the following language: 
“ Shell of the general appearance and surface characters of Retzia ; furnished 
with internal spires, pointing outward and downward ( ? ). Beak of ventral 
valve prominent, incurved, pointed; area emarginate in front, or V-shaped, 
reaching to the point of the beak, and extending forward of the beak of the 
dorsal valve on each side of it. Beak of the dorsal valve closely incurved, fill¬ 
ing, or nearly filling the forked space or emargination in the front part of the 
area, being itself without angular, hinged extensions, or area, to meet that of 
the opposite valve.” (White, loc, cit.) 
Specimens of this species are quite rare, and we have seen none in which 
the beak is perfectly retained. The structure of the beak and the absence of 
a foramen, as given by White, seem unnatural for a member of these retziiform 
shells, and in view of the author’s statement (p. 28) that his figures are to some 
degree restorations, this point will require careful re-examination. Nevertheless 
the species A. prima bears an internal pedicle-tube, as in Retzia and Hustedia, a 
character absent in Eumetria, while the exterior characters of the shell are 
* This species is i-eferred to the genus Acambona in db Koninck’s last work on the Faune du Calcaii-e 
Carbonifere de Belgique; Brachiopodes, Explic., id. xxii, figs. 25-31, 1889. Most of the figui-es given in 
this work, however, show a vei-y clearly developed foramen, on the absence of which the genus Acambona 
was based. Waagen, on the other hand, has more recently suggested that this rare species may prove con¬ 
generic with his Uncinella indica. 
